1. Field of the Invention
The present invention relates to a flexible endoscope in which an optical fiber of an optical transmission module that is arranged in a rigid distal end portion is inserted through an insertion portion.
2. Description of the Related Art
Endoscopes include an image pickup device such as a CCD in a distal end portion of an elongated flexible insertion portion. In recent years, the use of image pickup devices with a high pixel count in endoscopes is being studied. When an image pickup device with a high pixel count is used, because a signal amount that is transmitted to a signal processing apparatus (processor) from the image pickup device increases, optical signal transmission through a narrow optical fiber by means of optical signals is preferably employed instead of electrical signal transmission through metal wiring by means of electrical signals. In the optical signal transmission, an E/O module (electrical-optical converter) that converts electrical signals to optical signals, and an O/E module (optical-electrical converter) that converts optical signals to electrical signals are used.
For example, Japanese Patent Application Laid-Open Publication No. 2013-025092 discloses an optical transmission module including: an optical device that performs inputting or outputting of an optical signal; a substrate on which the optical device is mounted; and holding portions which have a through hole for inserting an optical fiber that is configured to transmit optical signals that are inputted to and outputted from the optical device, and which are arranged side by side in the thickness direction of the optical device.